Although there has been tremendous progress in the development and testing of interventions that have shown consistent, positive effects on outcomes in randomized trials with children and adolescents, over 90% of publicly-funded child service systems do not deliver treatments or services that have an evidence base to support them. As described in PA-04-019, research is needed on the movement of efficacious interventions into real world community settings. In this application, we propose to test the effectiveness of the Community Development Team (CDT), a theory-driven model to promote the adoption, implementation, and sustainability of one such intervention (Multidimensional Treatment Foster Care;MTFC) in California counties that are not already using MTFC. To examine the effectiveness of the CDT intervention, counties will be randomly assigned to the CDT plus Standard Implementation of MTFC (CDT) condition, or to the Standard Implementation of MTFC only (SI) condition. Both CDT and SI counties will receive the resources needed to implement MTFC, and counties will pay for all direct services to children and families. The CDT intervention model was developed by the California Institute for Mental Health (CIMH) in an effort to engage and support evidence-based programming throughout the state. In the proposed study, we will test whether a set of fixed contextual factors (i.e., being a CMHS System of Care site, level of poverty, urban/rural, presence of consumer advocacy, history of collaboration) moderate the hypothesized intervention effect. Additionally, we will examine whether changes in a set of dynamic contextual factors (i.e., psychological and organizational climate, and attitudes toward evidence-based practices) mediate the association between random assignment and the intervention effects. A multi-level intervention and assessment approach will be used that involves system decision makers, consumer representatives, agency administrators, practitioners, foster parents, and youth and their families. Analyses will examine group differences in the intervention outcomes (rates of adoption, implementation, and sustainability of MTFC), as well as the hypothesized moderating effects of fixed factors and the mediating effects of dynamic factors. The design of this study will provide information that increases the understanding of "what it takes" to engage and support uptake, implementation, and sustainability of evidence-based programs in communities.